Most people, by far, buy their cigarettes at convenience stores 63.4 percent, all told. Only 3.6 percent of people get them at drugstores.

So the CVS decision, by itself, isn't likely to turn the smoking tide.

Even so, CVS's stand could still be influential. The Wall Street Journalwrote that "CVS's move is expected to put pressure on its main rivals Walgreen, Rite Aid Corp. and even Wal-Mart Stores to adopt similar measures."

There's also a precedent north of the border. Canadian provinces and territories began banning the sale of cigarettes in pharmacies about 20 years ago. British Columbia is now the only province that doesn't restrict cigarette sales in privately owned drug stores, according to the CBC.